possible to use file as input (#152)

cli/src/main/scala/aqua/AppOps.scala

@@ -28,10 +28,18 @@ object AppOps {
     Validated
       .fromEither(Validated.catchNonFatal {
         val f = p.toFile
-        if (f.exists() && f.isDirectory) {
-          Right(p)
+        if (f.exists()) {
+          if (f.isFile) {
+            val filename = f.getName
+            val ext = Option(filename)
+              .filter(_.contains("."))
+              .map(f => f.substring(f.lastIndexOf(".") + 1))
+              .getOrElse("")
+            if (ext != "aqua") Left("File must be with 'aqua' extension")
+            else Right(p)
+          } else Right(p)
         } else {
-          Left(s"There is no path '${p.toString}' or it is not a directory")
+          Left(s"There is no path '${p.toString}'")
         }
       }.toEither.left.map(t => s"An error occurred on imports reading: ${t.getMessage}").flatten)
       .toValidatedNel
@@ -41,7 +49,7 @@ object AppOps {
     Opts
       .option[Path](
         "input",
-        "Path to the input directory that contains your .aqua files. It can only be a directory",
+        "Path to an aqua file or an input directory that contains your .aqua files",
         "i"
       )
       .mapValidated(checkPath)

cli/src/main/scala/aqua/AquaCli.scala

@@ -48,16 +48,19 @@ object AquaCli extends IOApp with LogSupport {
 
       // if there is `--help` or `--version` flag - show help and version
       // otherwise continue program execution
-      h.map(_ => helpAndExit) orElse v.map(_ => versionAndExit) getOrElse
+      h.map(_ => helpAndExit) orElse v.map(_ => versionAndExit) getOrElse {
+        val target = if (toAir) AquaCompiler.AirTarget else AquaCompiler.TypescriptTarget
+        val bc = {
+          val bc = BodyConfig(wrapWithXor = !noXor)
+          bc.copy(relayVarName = bc.relayVarName.filterNot(_ => noRelay))
+        }
         AquaCompiler
           .compileFilesTo[F](
             input,
             imports,
             output,
-            if (toAir) AquaCompiler.AirTarget else AquaCompiler.TypescriptTarget, {
-              val bc = BodyConfig(wrapWithXor = !noXor)
-              bc.copy(relayVarName = bc.relayVarName.filterNot(_ => noRelay))
-            }
+            target,
+            bc
           )
           .map {
             case Validated.Invalid(errs) =>
@@ -67,6 +70,7 @@ object AquaCli extends IOApp with LogSupport {
               results.map(println)
               ExitCode.Success
           }
+      }
     }
   }
 

cli/src/main/scala/aqua/AquaCompiler.scala

@@ -36,13 +36,16 @@ object AquaCompiler extends LogSupport {
 
     def targetPath(ext: String): Validated[Throwable, Path] =
       Validated.catchNonFatal {
+        val srcDir = if (srcPath.toFile.isDirectory) srcPath else srcPath.getParent
+        val srcFilePath = srcDir.toAbsolutePath
+          .normalize()
+          .relativize(modFile.toAbsolutePath.normalize())
+
         val targetAqua =
           targetPath.toAbsolutePath
             .normalize()
             .resolve(
-              srcPath.toAbsolutePath
-                .normalize()
-                .relativize(modFile.toAbsolutePath.normalize())
+              srcFilePath
             )
 
         val fileName = targetAqua.getFileName

cli/src/main/scala/aqua/io/AquaFiles.scala

@@ -21,10 +21,14 @@ object AquaFiles {
     // TODO use effect instead of Try
     EitherT
       .fromEither[F](
-        Try(sourcePath.toFile)
-          .filter(_.isDirectory)
-          .flatMap(d => Try(d.listFiles().toList))
-          .toEither
+        Try {
+          val f = sourcePath.toFile
+          if (f.isDirectory) {
+            f.listFiles().toList
+          } else {
+            List(f)
+          }
+        }.toEither
       )
       .leftMap[AquaFileError](FileSystemError)
       .leftMap(NonEmptyChain.one)